The present invention relates to a double-layer window which is attached with a shade roller unit, which is controlled to guide a shade into the window for stopping the light or to take up the shade from the window for passing the light.
In order to regulate the light passing through a window, a venetian blind or a shutter or a curtain may be used. When a venetian blind or a shutter or a curtain is used, it shall be installed in the wall or a frame on the wall adjacent to the window. Because the venetian blinds, the shutters and the curtains which are commonly used in building construction are inflammable, their use must be very careful and kept away from fire. Because a venetian blind or a shutter or a curtain may be contaminated easily, it must be regularly washed. Furthermore, a variety of double-layer windows are known and widely in use for the advantage of sound and heat isolating effects. However, because a double-layer window is consisted of two panels attached together with a space defined on the inside, much installation space is required, more particularly when a venetian blind or a shutter or a curtain is attached for regulating the light.